Process and apparatus for needle felting non-woven fabrics



.March 12, 1968 J, A, WILLIAMS ETAL 3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS 4Sheets-Sheet 1 Filed Feb. 28, 1966 mmmmmlzammmm 5 W m M .7 r z g 0 I KF: WM M March 12, 1968 J. A. WILLIAMS ETAL ,3

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb.28, 1966 4 Sheets-Sheet 2 ill? ,1

FOR/VEYS March 12, 1968 J. A. WILLIAMS ETAL 3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb.28, 1966 4 Sheets-Sheet s EMA 1 z( March 12, 1968 J. A. WILLIAMS ETAL3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb.28, 1966 4 Sheets-Sheet 4 Q a g United States Patent 3,372,447 PROCESSAND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS James A. Williams,Pearisburg, Va., and Ralph H. Balch,

Charlotte, N.C., assignors to Celanese Corporation of America, New York,N.Y., a corporation of Delaware Filed Feb. 28, 1966, Ser. No. 530,446 16Claims. (Cl. 28-4) ABSTRACT OF THE DISCLOSURE Non-woven fabrics areneedle punched in a continuous manner by a plurality of needles mountedon a revolving drum. The needles enter the moving non-woven fabric at anangle less than 90 with respect to the fabric and are withdrawn from thefabric in a substantially longitudinal motion.

and a mat is built upon the conveyor of many fibers laid on top of eachother. Very few of the fibers extend vertically through the mat and, asa result, there is practically no cohesion between the fibers in themat. The loose mat is not self-sustaining and would disintegrate if itwere removed from the conveyor. One method of improving the structuralintegrity of the mat is to pierce the mat with a plurality of needles.Usually, the needles have barbs and when they are forced through themat, the

barbs catch some of the fibers and draw them downward through the mat,so that the fibers become entangled with other fibers across thethickness of the mat.

In conventional needling apparatus, the needles are mounted in a framewhich reciprocates vertically with respect to a horizontally moving mat.The progress of the mat is stopped while the needles are lowered intothe mat and the mat is started again after the needles have beenwithdrawn from the mat. This step motion of the conveyor is necessarybecause the needle frame is not mounted for movement along with theconveyor. The step motion of the conveyor necessarily limits the rate ofproduction of non-woven fabrics. Another deficiency of the reciprocatingneedle arrangement is that the needles enter the fabric substantiallyperpendicularly and thus engage only the fibers that are directly in thepath of the needles. In order to get maximum entanglement of the fibersby the needling process, therefore, it is necessary to utilize a greatmany needles closely spaced together. This greatly increases the cost ofthe apparatus, it close entanglement of fibers is desired.

Accordingly, it is an object of this invention to provide an improvedneedling process and apparatus.

It is a further object of this invention to provide a method andapparatus for needling non-woven fabrics or mats on a conveyor whilecontinuously advancing the conveyor.

It is a still further object of this invention to provide a method andapparatus for causing maximum entanglement of fibers in non-wovenfabrics or mats.

3,372,447 Patented Mar. 12, 1968 These objects are accomplished inaccordance with the preferred embodiment of the invention by mounting aplurality of needles on a revolving drum and changing the positions ofthe needles with respect to the non-woven mat as the needles approachand move away from the mat. In one embodiment, the needles are offsetwith respect to the axis of rotation of the drum and are quicklywithdrawn from the mat by longitudinal motion of the needles. The motionof the needles is controlled in such a manner that the needles penetratethe mat and are quickly withdrawn while the drum is rotating and the matis moving continuously under the drum. In another embodiment of theinvention, the needles are mounted for swinging motion in radial planeswith respect to the drum. The positions of the needles are controlled sothat they point toward the mat as they approach the mat, but the matmoves at a slower speed than the drum, which causes the needles to swingrearwardly prior to being withdrawn from the mat. Thus, the needles arewithdrawn approximately longitudinally to produce maximum entanglementof thefibers. The needles are barbed for catching fibers upon movementinto the mat and also upon movement back out of the mat. In this secondembodiment of the invention, a greater degree of entanglement of fibersis produced at the center of the that than at the surface of the mat.

These preferred embodiments of the invention are illustrated in theaccompanying drawings, in which:

FIGURE 1 is a schematic view of the needling apparatus of thisinvention;

FIGURE 2 is a front elevational view of the needling drum;

FIGURE 3 is a cross sectional view of the drum along the line 33 inFIGURE 2;

FIGURE 4 is a cross sectional view of the drum along the line 4-4 inFIGURE 3;

FIGURE 5 is a cross sectional view as in FIGURE 3, but of a modifiedform of the invention; and

FIGURE 6 is across sectional view of the modified drum along the line6-6 in FIGURE 5.

Non-woven fabrics are made up of loose fibers that are joined togetherby random entanglement rather than weaving. One method of producingnon-woven fabrics is to deposit the fibers on a moving conveyor 2, asshown in FIGURE 1. The fibers may be deposited on the conveyor 2 as itpasses through a chamber 4. The fibers are laid on top of each other toform a mat 6 on the conveyor 2. A revolving drum 8 is mounted over theconveyor 2 and extends transversely across the mat 6.

The drum 8, as shown in FIGURE 2, includes an outer cylinder 10 which ismounted for rotation on a stationary, non-rotating shaft 12. The shaftis supported tionary shaft 12.

A plurality of needle assemblies 26 are arranged in rows extendingaround the circumference of the cylinder 10 and the rows of needleassemblies 26 are spaced apart uniformly along the length of thecylinder 10. The spac- 3 ing between the rows of needle assemblies 26,as shown in FIGURE 2, is merely illustrative. The needle assemblies maybe positioned closer together or further apart, as required. Preferably,the needle assemblies in adjacent rows are staggered.

Referring to FIGURE 3, the needle assemblies 26 include a barbed needle28 and a needle holder 30. The needles have barbs pointing in oppositedirections. In each assembly 26, the base of the needle 28 is secured ina plug or cap 32. The needle holder 30 is in the form of a hollow tubeand the cap 32 is secured on the end of the tube by a conventionalbayonet fastener 34, or any other suitable means. The cylinder has aplurality of internal bosses 36, each of which has a tangential bore 38in which the holder 30 is mounted. The needles 28 are pointed in thedirection of rotation of the cylinder 10. The central axis of eachneedle is positioned at approximately right angles to a radius of thecylinder 10. With this orientation, the needles enter the mat at anangle less than 90 with respect to the mat surface. Preferably, theangle of entry is between 30 and 60.

The holders 30 are received in the respective bores 38 and each of theholders is spring-biased toward movement inwardly with respect to thecylinder 10. A spring 40 is mounted in each of the holders adjacent theclosed end and the holders have a longitudinal slot 42 through which ascrew 44 extends. The screw 44 is threaded into a hole in the cylinder10 and the slot 32 allows the holder to move longitudinally relative tothe screw 44. The screw compresses the spring 40 against the closed endof the needle holder 30. Thus, the spring 40 urges the holder inwardlywith respect to the cylinder 10.

The positions of the needle holders 30 with respect to the cylinder 10are controlled by cam followers 46. As shown in FIGS. 3 and 4, the camfollowers 46 are mounted for swinging movement about a pivot pin 48which is rigidly supported by a ring 50 extending radially around theinterior of the cylinder 10. The ring 50 is welded or otherwise securedto the interior surface of the cylinder 10 and rotates with thecylinder. Each of the cam followers 46 has an arm 52 which bears againsta stationary annular cam 54. The cam 54 is supported by a hub 56 withradial spokes 58 interconnecting the hub and the cam. The hub 56 isrigidly secured to the stationary shaft 12 by means of a key 60 which isreceived in a key slot 62 in the shaft 12. Preferably, each of the rowsof needle assemblies has a separate cam 54.

The cylinder 10 is mounted on the shaft 12 for rotation relative to theshaft. The mounting for the cylinder includes a hub 64 and radial spokes66 between the hub and the cylinder. The hub 64 turns freely about theshaft 12. Preferably, a plurality of hubs and spokes are spaced alongthe length of the cylinder 10. In order to provide staggered rows ofneedle assemblies, the hubs 56 are angularly offset from the hubs 56 ofadjacent needle cam assemblies in such a manner that the path of theneedles in each of the cam assemblies is substantially the same withrespect to the mat 6.

The profile of the cam surface is shown in FIGURE 3. The cam followerarms 52 are urged against the surface of the stationary cam 54 by thesprings 40 in each of the needle holders 30. As the needle assembliesmove clockwise with the cylinder 10, as viewed in FIGURE 3, the needleholders 30 are fully extended with respect to the cylinder 10 as theyapproach the mat 6. As the needles enter the mat 6, the respective camfollowers approach the fall portion of the cam 54 which causes thefollowers 46 to swing about the pivot pin 48. As the cam follower arm 52passes over the fall portion of the cam, the follower 46 swings to itslowermost position on the cam, allowing the needle holder 30 to beretracted rapidly into the cylinder 10 by the spring 40. This movementcauses the needle to be withdrawn from the mat 6 in a substantiallylongitudinal motion. Then, after the needle 28 has moved clear of themat 6, the cam follower 4 is pivoted by the rise portion of thestationary cam back t the extended position where it remains until theneedle assembly again approaches the mat 6.

Preferably, the needles 28 are sutficiently long to pierce the fulldepth of the mat and project a short distance below the mat, as shown inFIG. 3. In order to prevent interference between the needles and theconveyor 2, grooves 68 may be provided in the conveyor 2. Also, sincebarbs on the needle 28 engage the fibers in the mat to draw themtransversely along the direction of movement of the needles, there maybe a tendency for some of the fibers to remain on the needles when theneedles are withdrawn from the mat. Accordingly, it may be necessary toprovide a stripper plate 70 above the mat 6. The plate 70 haslongitudinal slots 72 through which the needles pass. The slots 72 arepreferably narrow, so that they will pull off any fibers that areretained on the needles as they are withdrawn from the mat.

In operation, the speed of the conveyor 2 is adjusted to advance the mat6 at a uniform speed under the drum 8. The drum has approximately thesame surface speed or a slower surface speed than the mat 6. Theclockwise rotation of the cylinder 10, as viewed in FIGURE 3, advancesthe needles 28 sequentially into the mat. When the needles have piercedthe mat 6, they are immediately retracted by swinging movement of thecam followers 46 in moving through the fall portion of the cam 54. Thespring loaded needle holders are urged inwardly with respect to thecylinder 10 by the internal springs 40 as they reach the point ofmaximum penetration of the mat. Then after the needles 28 have beenwithdrawn from the mat 6, the cam followers 46 rotate to move theneedles 28 toward the outermost position where they remain until theyengage the mat again.

A modified form of the invention is shown in FIG URES 5 and 6. The drum8, as shown in FIGURES 1, 2 and 3, is modified to include a cylinder 74,on which are mounted needle assemblies 76 that are arranged insubstantially the same manner as the needle assemblies 26, shown inFIGURE 2. The needle assemblies 76 are mounted for swinging movementrelative to the cylinder 74 and the positions of the needles arecontrolled by a stationary cam 78 inside the cylinder 74.

Each needle assembly 76 includes a needle 80 which has its base mountedin a hub 82 and an arm 84 which projects outwardly on the opposite sideof the hub. On the end of the arm 84, there is a cam follower 86 whichprojects laterally from the arm 84. The hubs 82 are mounted for swingingmovement relative to the cylinder 74 by hearing blocks 88 on oppositesides of the hubs. Openings 90 are provided in the cylinder 74 forreceiving the respective hubs 82. Of course, other suitable arrangementsmay be provided for mounting the hubs 82 for pivoting movement relativeto the cylinder 74.

As shown in FIG. 6, the cylinder 74 is mounted for rotation on the shaft12 by means of a hub 92 with radial spokes 94 extending between the hub92 and the cylinder 74. The stationary cam 78 is also supported on theshaft 12 by means of a hub 96. The hub 96 is prevented from rotatingrelative to the shaft 12 by a conventional key 98 which is received in akey slot 100. Spokes 102 project outwardly from the hubs 96 forsupporting the stationary cam 78.

The cam 78 has an annular groove 104 in the side adjacent the needleassemblies 76. The groove 104 includes a narrow portion 106 and a wideportion 108 interconnecting the ends of the narrow portion 106. Thenarrow portion 106 of the groove 104 is slightly wider than the diameterof the cam followers 86, while the wide portion 108 is sufficiently wideto allow the arms 84 to swing freely about the hubs 82. At the junctionof the wide portion 108 and the narrow portion 106, the side of thegroove 1438 forms a rise cam surface 110 which swings the needle aroundto point in the opposite direction and guides the follower 86 into thenarrow portion 106 of the groove.

As the cylinder 74 rotates, the needles 80 are guided into the mat 6,but while the cam follower is in the wide portion 108 of the groove 104,the needle is free to turn about the hub 82. The movement of thecylinder 74 at a greater surface speed than the mat 6 causes the needleto swing from a forwardly pointing direction to a rearwardly pointingdirection, as shown in FIG. 5. Withdrawal of the needle occurs while theneedle is pointing in a rearwardly direction. When the relative speedsof the cylinder 74 and the mat 6 are properly adjusted, the needlespierce the mat by substantially longitudinal movement of the needlesrelative to the mat. The needles are also withdrawn by substantiallylongitudinal movement of the needles and during such movement the barbson the needles catch some of the fibers in the mat and draw them alongthe direction of movement of the needles. The needles have barbspointing in opposite directions to catch the fibers as the needles passinto and back out of the mat 6.

The belt conveyor 2 under the mat 6 may be in the form of a plurality ofindividual belts 68 which are spaced apart sufiiciently to allow theneedles 80 to pass between the belts. The gaps between the belts shouldbe aligned with the rows of needle assemblies 76 on the surface of thedrum. Also, a stripper plate 70 is preferably positioned above the matto remove the fibers remaining on the needles after they have beenwithdrawn from the mat.

In operation, the speed of the mat 6 is adjusted to be slower than thesurface speed of the cylinder 74. As the needle assemblies 76 approachthe mat 6, the needles 80 are guided by the cam groove 104 to pointtoward the mat as shown in FIG. 5. The relative distance between thecylinder 74 and the mat 6 is adjusted, so that the pointed end. of theneedle 80 enters the mat as the corresponding follower 86 enters thewide portion 108 of the cam groove 104. While the needle is inengagement with the mat, it swings to a rearwardly pointing position.After the needle has been withdrawn from the mat, the cam follower 86 ofthe needle assembly engages the rise portion 110 of the cam groove 104to swing the needle 80 around so that it is in a forwardly pointingposition before entering the narrow portion 106 of the groove 104.

The path of motion of the needles 80, as shown in FIGURE 5, causes ahigh degree of entanglement of fibers at the center of the mat adjacentthe point about which the needles swing. At the surfaces of the mat, theneedle moves transversely relative to the mat, causing a looseentanglement of fibers at the surfaces of the mat. The resulting matresembles a napped woven fabric. This structure of the mat is desirablebecause of its good drape qualities and raised or napped surface.

It is apparent that the needles 28 and 80 of the apparatus of thisinvention enter the mat and remain in the mat for a considerably shorterduration than would be possible if merely radial needles were providedon the surface of the cylinder of the drum 8. Also, instead of sweepingthrough the mat, the needles penetrate the mat primarily in alongitudinal motion. Accordingly, the mat produced by the apparatus ofthis invention has a plurality of fibers that are drawn generallyperpendicular to the direction of motion of the mat and are entangledwith the adjacent fibers in the mat and the result is that the strengthof the mat has been considerably increased. Furthermore, since the matmoves continuously during the needling operation, the apparatus achievesa high production rate and there is no need to provide for intermittentmotion of the mat as is necessary with reciprocating type needlingdevices.

It is desirable for the points at which the needles penetrate the mat tobe close together in order to obtain maximum entanglement of the fibers.As previously stated, the needle assemblies in adjacent rows may bestaggered for this purpose. Another alternative is to provide a seriesof staggered drums 8 along the length of the mat 6 with the drumsrotating in fixed angular relations with each other. Thus, the needlesof the subsequent drums would penetrate the mat at points between thepenetration points of the needles in preceding drums.

. While this invention has been illustrated and described in severalembodiments, it is recognized that variations and changes may be madetherein without departing from the invention as set forth in the claims.

We claim:

1. A method of needle felting a non-woven fabric comprising elfectingcontinuous motion of said fabric along a substantially straight path,piercing said fabric with needles, and withdrawing said needles from thefabric in a substantially longitudinal motion.

2. A method of needle felting a non-woven fabric according to claim 1including moving said needles in an arcuate path.

3. A method of needle felting a non-woven fabric according to claim 2including changing the position of said needles relative to said arcuatepath while said needles are in engagement with said fabric.

4. A method of needle felting a non-woven fabric according to claim 1including changing the orientation of said needles relative to saidfabric while piercing said fabric.

5. A method of needle felting a non-woven fabric according to claim 4including moving said needles and said fabric in substantially the samedirection, said needles moving at a greater speed than said fabric.

6. Apparatus for needle felting non-woven fabrics comprising a pluralityof needles, means for moving said needles in an arcuate path and meansfor changing the position of said needles relative to said path, wherebythe needles are withdrawn from the fabric in a substantiallylongitudinal motion.

7. Apparatus for needle felting according to claim 6 wherein said movingmeans includes a drum, said needles being mounted in said drum, andmeans for rotating said drum.

8. Apparatus for needle felting according to claim 7 wherein said drumincludes a cylinder and cam means, means mounting said needles in saidcylinder, means for rotating said cylinder relative to said cam means,and means on said needless for engaging said cam means, whereby said cammeans controls the position of said needles relative to said cylinder.

9. Apparatus for needle felting according to claim 7 wherein saidneedles are positioned generally tangentially of said cylinder.

10. Apparatus for needle felting according to claim 9 wherein saidneedle mounting means includes means cooperating with said cam means forindividually displacing said needles longitudinally.

11. Apparatus for needle felting according to claim 8 wherein saidneedles are mounted for swinging movement relative to said cylinder,said cam means restricting swinging movement of said needles during aportion of each revolution of said cylinder and releasing said needlesfor swinging movement during another portion of each revolution.

12. In needle felting apparatus of the type having a movable conveyor onwhich non-woven fabrics are supported, a needle felting drum, aplurality of needles projecting outwardly from said drum, means forrotating said drum, said fabrics being in position on said conveyor tobe pierced by said needles, and means for withdrawing said needles fromthe fabric by substantially longitudinal movement of said needlesrelative to said conveyor, said drum rotating continuously and saidconveyor moving continuously relative to the drum.

13. The apparatus according to claim 12 wherein said conveyor supportssaid fabric on a substantially planar surface parallel to the centralaxis of said drum.

14. The apparatus according to claim 13 including means for guiding saidneedles into said fabric, said needles engaging said fabric whileinclined relative to the plane of said fabric and pointing in thedirection of rotation of said drum.

15. The apparatus according to claim 14 wherein said needles are mountedfor swinging movement while in engagement with said fabric, saidconveyor moving said fabric at a slower surface speed than that of saidneedles, whereby the fabric causes the needles to swing from forwardlyinclined to rearwardly inclined positions.

16. Apparatus for needle felting according to claim 6 wherein saidneedles have barbs projecting in opposite longitudinal directions.

References Cited UNITED STATES PATENTS 5 2,920,373 1/1960 Gresham 2872.23,025,585 3/1962 Griswold 28-1 3,038,215 6/1962 Harwood 19-161 3,208,1259/1965 Hall et al. 284

10 LOUIS K. RIMRODT, Primary Examiner.

